1 files changed, 86 insertions, 0 deletions
diff --git a/src/engine/e_compression.cpp b/src/engine/e_compression.cpp
new file mode 100644
index 00000000..f4d6e0c0
--- /dev/null
+++ b/src/engine/e_compression.cpp
@@ -0,0 +1,86 @@
+/* copyright (c) 2007 magnus auvinen, see licence.txt for more info */
+#include <base/system.h>
+
+/* Format: ESDDDDDD EDDDDDDD EDD...  Extended, Data, Sign */
+unsigned char *vint_pack(unsigned char *dst, int i) 
+{ 
+	*dst = (i>>25)&0x40; /* set sign bit if i<0 */
+	i = i^(i>>31); /* if(i<0) i = ~i */
+
+	*dst |= i&0x3F; /* pack 6bit into dst */
+	i >>= 6; /* discard 6 bits */
+	if(i)
+	{
+		*dst |= 0x80; /* set extend bit */
+		while(1)
+		{
+			dst++;
+			*dst = i&(0x7F); /* pack 7bit */
+			i >>= 7; /* discard 7 bits */
+			*dst |= (i!=0)<<7; /* set extend bit (may branch) */
+			if(!i)
+				break;
+		}
+	}
+
+	dst++;
+	return dst; 
+} 
+ 
+const unsigned char *vint_unpack(const unsigned char *src, int *i)
+{ 
+	int sign = (*src>>6)&1; 
+	*i = *src&0x3F; 
+
+	do
+	{ 
+		if(!(*src&0x80)) break;
+		src++;
+		*i |= (*src&(0x7F))<<(6);
+
+		if(!(*src&0x80)) break;
+		src++;
+		*i |= (*src&(0x7F))<<(6+7);
+
+		if(!(*src&0x80)) break;
+		src++;
+		*i |= (*src&(0x7F))<<(6+7+7);
+
+		if(!(*src&0x80)) break;
+		src++;
+		*i |= (*src&(0x7F))<<(6+7+7+7);
+	} while(0);
+
+	src++;
+	*i ^= -sign; /* if(sign) *i = ~(*i) */
+	return src; 
+} 
+
+
+long intpack_decompress(const void *src_, int size, void *dst_)
+{
+	const unsigned char *src = (unsigned char *)src_;
+	const unsigned char *end = src + size;
+	int *dst = (int *)dst_;
+	while(src < end)
+	{
+		src = vint_unpack(src, dst);
+		dst++;
+	}
+	return (long)((unsigned char *)dst-(unsigned char *)dst_);
+}
+
+long intpack_compress(const void *src_, int size, void *dst_)
+{
+	int *src = (int *)src_;
+	unsigned char *dst = (unsigned char *)dst_;
+	size /= 4;
+	while(size)
+	{
+		dst = vint_pack(dst, *src);
+		size--;
+		src++;
+	}
+	return (long)(dst-(unsigned char *)dst_);
+}
+